Apparatus for regulated delivery of a gas, in particular breathing apparatus

ABSTRACT

This apparatus ( 1 ) includes an air intake duct, a volute ( 5 ) of which the inlet opening ( 22 ) communicates with the air intake duct, a first vane rotor ( 4 ) located immediately downstream of the inlet opening ( 22 ) of the volute ( 5 ), a motor ( 3 ) for driving the rotor ( 4 ), and a motor ( 3 ) for rotating the rotor ( 4 ) in order to generate a centrifugal air flow in the volute ( 5 ). The apparatus further includes:
         a casing ( 2 ) having a tubular portion ( 10   a ) located at a substantially constant distance from the motor ( 3 ), the casing ( 2 ) and the motor ( 3 ) thereby together bounding a gas flow passage ( 15 ) including at least one gas inlet orifice ( 20 ) and at least one gas outlet orifice ( 16 ); and   a second vane rotor ( 6 ) located downstream of the gas inlet orifice ( 20 ) rotated in order to generate a forced gas stream in the gas flow passage ( 15 ).

The present invention relates to an apparatus for regulated delivery of a gas, in particular a breathing apparatus.

Document DE 37 10 622 teaches how to prepare a breathing apparatus comprising an air intake duct, a volute of which the inlet opening communicates with the air intake duct, a first vane rotor, located immediately downstream of the inlet opening of the volute, comprising an inlet opening connected to this inlet opening of the volute and outlet orifices opening into the volute, and a motor for rotating the rotor in order to generate a centrifugal air flow in the volute; this apparatus further comprises:

-   -   a casing having a tubular portion of which the wall is intended         to extend, after assembly, around the motor and remaining at a         substantially constant distance from this motor, the casing and         the motor thereby together bounding a gas flow passage         comprising at least one gas inlet orifice and at least one gas         outlet orifice; and     -   a second vane rotor located downstream of said gas inlet         orifice, rotated in order to generate a forced gas stream in         said gas flow passage.

The shaft of the motor is mounted on ball bearings.

This existing apparatus has the prohibitive drawback of incurring a risk, in case of destruction of one or the other of the ball bearings, of an ejection of the balls from this bearing into the volute and therefore into the circuit of air delivered to the patient.

The existing apparatus also has the drawback of permitting a direct exchange of the gas fed to the volute with the motor compartment, so that the cooling of the motor depends on the gas flow rate in the volute.

Furthermore, the lifespan of the ball bearings of the vane rotors of this apparatus appears to be reduced.

It is the object of the present invention to remedy all these drawbacks.

The apparatus that it relates to comprises the abovementioned known features.

According to the invention, the apparatus comprises a plate traversed by the shaft of the motor, extending close to the wall of said first vane rotor opposite the inlet of the volute, and the casing comprises orifices causing communication between the side of this plate opposite said first vane rotor and said gas flow passage.

Thus, according to the invention, in case of destruction of one or the other of the shaft ball bearings, the plate serves to eliminate any risk of the introduction of the balls of this bearing into the gas delivery circuit.

Moreover, the plate serves to bound two essentially separate circuits, that is the main gas delivery circuit, comprising said first vane rotor and the volute, and the motor coolant gas circuit. Optimal cooling of the motor can be obtained independently of the gas flow rate in the main circuit, including when this flow rate is zero.

Furthermore, said orifices of the casing permit the flow, in said passage, of the pressurized gas flowing through the interstice necessarily existing between the shaft bearing said first vane rotor and the plate, and this gas leakage is collected by the motor coolant gas circuit and is removed with it. This leakage gas stream promotes the cooling of the part of the motor closest to said first vane rotor.

A further advantage of the invention is, thanks to said plate, in permitting the establishment of environmental conditions of the two ball bearings that are favorable to the lifespan of these bearings: the plate serves to create a slight pressure difference between the two sides of the motor and therefore to minimize the flushing of gas and any dust when passing through the bearings.

Preferably, said second vane rotor is placed on a shaft driven by the motor.

Thus, the speeds of rotation of the two vane rotors are identical, so that the speed of rotation of the second vane rotor and hence the cooling of the motor, can be adapted to the motor cooling requirements corresponding to the speed of rotation of said first vane rotor.

The apparatus also has a simple structure and, since said second vane rotor only generates a slight pressure, its power consumption is low and does not significantly deteriorate the energy balance of the operation of the apparatus.

Preferably, the casing comprises a plurality of gas outlet holes distributed on the circumference of this casing, and the casing comprises a circular chamber arranged at these gas outlet holes comprising a gas outlet manifold.

This circular chamber serves to collect the coolant gas, which can be reused. In fact, the temperature rise of this gas remains slight, about 10° C. in extreme conditions; hence the flow of this gas can be used for example to cool other members, in particular sensitive components, such as electronic circuit boards or batteries for self-contained operation of the apparatus.

Advantageously, said circular chamber forms a body with the casing, at least in part.

The ventilation gas is preferably air, said gas inlet orifice opening directly onto the exterior of the casing.

This orifice allows an entry of air into said flow passage without disturbing this flow and without generating any noise.

The orifices of the casing causing communication between the side of the plate opposite said first vane rotor and said coolant gas flow passage are advantageously arranged at distant locations, in the radial direction, of the shaft of the motor.

This distancing serves to maximize the path of the leakage gas stream between, the plate and the wall comprising said orifices, and thereby to promote the cooling of the motor on the side of said first vane rotor. Moreover, said orifices are thereby brought closer to the coolant gas outlet holes outside the casing, favoring the flow of this leakage stream.

The invention will be well understood, and other features and advantages thereof will appear, with reference to the appended schematic drawing, which shows, as a nonlimiting example, one possible embodiment of the apparatus that it concerns.

FIG. 1 is a view of this apparatus, in an axial section along the axis of the shaft which this apparatus comprises and in a plane substantially parallel to the axis of the outlet manifold which the volute of this apparatus comprises, and

FIG. 2 is a detailed view, at a larger scale.

FIG. 1 shows an apparatus 1 for regulated delivery of a gas, in particular a breathing apparatus, comprising a casing 2, a motor 3, a first vane rotor 4, a volute 5, a second vane rotor 6 and a collecting chamber 7.

The casing 2 comprises a main part 10, two end covers 11, 12 and a median cover 13.

The main part 10 forms a tubular portion 10 a, for accommodating the motor 3, a transverse wall 10 b bounding one longitudinal end of this tubular portion 10 a, a circular wall 10 c extending around this longitudinal end of the tubular portion 10 a, and a circular wall 10 d which forms the base of the volute 5.

The wall of the tubular portion 10 a extends, after assembly, around the motor 3 and at a substantially constant distance from this motor, so that this tubular portion 10 a and the motor 3 together bound an air flow passage 15.

This tubular portion 10 a comprises, substantially at the height of the free edge of the circular wall 10 c, a series of radial holes 16, and the transverse wall 10 b comprises, at its periphery, a series of orifices 17 passing through it. These orifices 17 are arranged at distant locations, in the radial direction, of the shaft of the motor 3, and are therefore close to the holes 16.

The end cover 11 is intended to be placed on the free edge of the tubular portion 10 a opposite the volute 5. It comprises an axial opening 20 facing the rotor 6 after assembly.

The end cover 12 comprises a part having a circular or spiral shape, intended to be placed on the free edge of the wall 10 d, to constitute, with this wall 10 d, the volute 5, and a part intended to constitute, with a corresponding part of the wall 10 d, a tangential outlet manifold 21. This cover 12 forms an inlet opening 22 facing the rotor 4 after assembly, this opening 22 being in communication with an air intake duct (not shown) bounded by a casing (not shown) containing the apparatus 1.

The median cover 13 comprises a circular part intended to be placed on the free edge of the wall 10 c, to constitute, with this wall 10 c, the collection chamber 7, and a part intended to constitute, with a corresponding part of the wall 10 c, an outlet manifold 23.

The motor 3 has a cylindrical shape and is axially connected to the transverse wall 10 b, by means of screws (not shown). It comprises an outlet shaft projecting beyond its two axial ends, one of the projecting parts of this shaft accommodating the rotor 4 and the other projecting part accommodating the rotor 6.

This shaft is mounted on ball bearings, located respectively close to the rotor 4 and the rotor 6.

The rotor 4 comprises a hub, an upper flange and a bottom wall forming an air flow duct in which the vanes 4 a of this rotor 4 extend. The upper flange forms a raised circular ledge immediately approaching the wall of the cover 12 bounding the opening 22.

The rotation of the rotor 4 at high speed, driven by the motor 3, generates a centrifugal air flow of which the kinetic energy is converted to pressure in the volute 5, this air entering via the opening 22 and exiting via the manifold 21.

The apparatus 1 further comprises a plate 25 traversed by the shaft of the motor 3, which extends close to the bottom wall of the rotor 4, this plate bearing against a circular seat arranged in the end of the tubular portion 10 a and being attached thereto. The orifices 17 cause the side of this plate 25 opposite the rotor 4 to communicate with the passage 15.

As may be understood, the rotation of the rotor 6 by the motor 3 serves to generate a forced air stream in the passage 15, and then through the holes 16, into the chamber 7 and into the manifold 23. The passage 15 extends over the entire circumference of the motor 3 and has a continuous configuration, without a substantial variation in cross section, thereby serving to cool the motor 3 under ideal conditions. The air flow cooling the motor 3 is independent of the gas flow in the gas delivery circuit, so that the use of the apparatus has no effect on the cooling of the motor. This cooling is thus sufficiently effective even if the flow of the gas delivery circuit is zero.

The direct assembly of the rotors 4 and 6 on the same shaft of the motor 3 allows the speeds of rotation of the two vane rotors 4, 6 to be identical, thereby allowing the permanent adjustment of the cooling of the motor 3 to the speed of rotation of the rotor 4, hence to the operating speed of the apparatus 1.

The apparatus 1 also has a simple structure and, since the rotor 6 only generates a slight pressure, its power consumption is low and does not significantly deteriorate the energy balance of the operation of this apparatus.

The collection chamber 7 serves to collect the cooling air so that it can be reused, for example, to cool other members, in particular sensitive components such as electronic circuit boards or batteries for self-contained operation of this apparatus.

The plate 25, in case of destruction of one or the other of the ball bearings of the motor shaft, serves to eliminate any risk of the introduction of the balls of this bearing into the gas delivery circuit.

This plate 25 also serves to limit the leakage of pressurized gas contained in the volute 5, which occurs via the interstice that necessarily exists between this plate and the shaft bearing the rotor 4 (cf. FIG. 2). The orifices 17 allow the flow of this leak into the passage 15, this leak being collected by the cooling air circuit of the motor 3 and removed therewith. Moreover, the leakage gas stream promotes the cooling of the part of the motor 3 closest to the rotor 4. This arrangement serves to establish, thanks to said plate 25, environmental conditions of the two ball bearings that are favorable to the lifespan of these bearings: the plate 25 serves to allow a slight pressure difference to exist between the two sides of the motor 3 and therefore to minimize the flushing of gas and any dust on passing through the bearings.

The apparatus according to the invention thus has decisive advantages over similar apparatus of the prior art.

The invention has been described above with reference to an embodiment provided purely as an example. It goes without saying that it is not limited to this embodiment but extends to all embodiments covered by the claims appended hereto. 

1. An apparatus (1) for regulated delivery of a gas, in particular breathing apparatus, comprising an air intake duct, a volute (5) of which the inlet opening (22) communicates with the air intake duct, a first vane rotor (4), located immediately downstream of the inlet opening (22) of the volute (5), comprising an inlet opening connected to this inlet opening (22) of the volute (5) and outlet orifices opening into the volute (5), and a motor (3) for rotating the rotor (4) in order to generate a centrifugal air flow in the volute (5), characterized in that it comprises: a casing (2) having a tubular portion (10 a) of which the wall is intended to extend, after assembly, around the motor (3) and remaining at a substantially constant distance from this motor (3), the casing (2) and the motor (3) thereby together bounding a gas flow passage (15) comprising at least one gas inlet orifice (20) and at least one gas outlet orifice (16); and a second vane rotor (6) located downstream of said gas inlet orifice (20), rotated in order to generate a forced gas stream in said gas flow passage (15).
 2. The apparatus (1) as claimed in claim 1, characterized in that said second vane rotor (6) is placed on a shaft driven by the motor (3).
 3. The apparatus (1) as claimed in claim 1, characterized in that the casing (2) comprises a plurality of gas outlet orifices (16) distributed on the circumference of this casing (2), and in that the casing (2) comprises a circular chamber (7) arranged at these gas outlet orifices (16) comprising a gas outlet manifold (23).
 4. The apparatus (1) as claimed in claim 3, characterized in that said circular chamber (7) forms a body with the casing (2).
 5. The apparatus (1) as claimed in claim 1, characterized in that said gas inlet orifice (20) opens directly onto the exterior of the casing (2).
 6. The apparatus (1) as claimed in claim 1, characterized in that the ventilation gas is air, said gas inlet orifice (20) opening directly onto the exterior of the casing (2).
 7. The apparatus (1) as claimed in claim 1, characterized in that it comprises a plate (25) traversed by the shaft of the motor (3), extending close to the wall of said first vane rotor (4) opposite the inlet (22) of the volute (5), and in that the casing (2) comprises orifices (17) causing communication between the side of this plate (25) opposite said first vane rotor (4) and said gas flow passage (15).
 8. The apparatus (1) as claimed in claim 2, characterized in that the casing (2) comprises a plurality of gas outlet orifices (16) distributed on the circumference of this casing (2), and in that the casing (2) comprises a circular chamber (7) arranged at these gas outlet orifices (16) comprising a gas outlet manifold (23).
 9. The apparatus (1) as claimed in claim 8, characterized in that said circular chamber (7) forms a body with the casing (2).
 10. The apparatus (1) as claimed in claim 2, characterized in that said gas inlet orifice (20) opens directly onto the exterior of the casing (2).
 11. The apparatus (1) as claimed in claim 2, characterized in that the ventilation gas is air, said gas inlet orifice (20) opening directly onto the exterior of the casing (2).
 12. The apparatus (1) as claimed in claim 2, characterized in that it comprises a plate (25) traversed by the shaft of the motor (3), extending close to the wall of said first vane rotor (4) opposite the inlet (22) of the volute (5), and in that the casing (2) comprises orifices (17) causing communication between the side of this plate (25) opposite said first vane rotor (4) and said gas flow passage (15). 